Validation of AIRS-Retrieved atmospheric temperature data over the Taklimakan Desert
Validation of AIRS-Retrieved atmospheric temperature data over the Taklimakan Desert
复制标题
塔克拉玛干沙漠AIRS反演大气温度数据的验证
DOI：
10.3724/sp.j.1226.2020.00242
复制
发表时间：
2020-09
影响因子：
1
通讯作者：
Ali Mamtimin
中科院分区：
文献类型：
--
作者：
Ma Yufen;Li Ruqi;Zhang Men;Wang Minzhong;Ali Mamtimin
塔克拉玛干沙漠是世界第二大沙漠，在区域气候变化中发挥着重要作用。先前对其空间温度特征的研究受到传统探测数据稀疏的影响，但大气红外探测器（AIRS）提供了具有高时空分辨率的出色温度反演。在将这些数据用于区域天气/气候建模之前，必须对地表发射率高的沙漠地区的 AIRS 温度反演进行验证，而沙漠地区是反演误差的关键因素。本文研究了AIRS反演大气温度数据与塔克拉玛干沙漠腹地和绿洲早晨和黄昏的无线电探空仪观测数据之间的相关系数、均方根误差(RMSE)和平均BIAS。首先，AIRS 检索与 RAOB 一致，并且早上比黄昏更一致。早晨，小规模沙漠绿洲的一致性优于大面积绿洲，黄昏时表现出相反的趋势。由于沙漠表面发射率较高，内陆地区的相关系数在早晨较高，但在黄昏时为负值。其次，早晨的RMSE均小于3 K，沙漠地区普遍高于绿洲地区，小规模绿洲地区略低于大范围绿洲地区。黄昏时，沙漠地区的 RMSE 高于绿洲，小规模绿洲的 RMSE 略高于大型绿洲。此外，大范围绿洲的 RMSE 通常在早晨高于黄昏，而在小范围绿洲则早晨低于黄昏。第三，绝对平均BIAS值大多低于1 K。早晨，相对于RAOB温度，沙漠站点反演温度较高，而绿洲站点反演温度较低。黄昏时，沙漠和绿洲站点的反演温度均低于 RAOB 温度。沙漠地区早晨反演温度高于RAOB温度，黄昏时反演温度略低。在绿洲和沙漠地区，大多数绝对平均 BIAS 值在早晨都高于黄昏。最后，AIRS和RAOB温度数据在早晨700 hPa至100 hPa和黄昏700 hPa至300 hPa之间的一致性较高。 AIRS和RAOB温度数据之间的差异一般在早晨比黄昏更大。 AIRS 和 RAOB 资料之间的 RMSE 差异在早晨略低于黄昏，并且在早晨和夜间，700 hPa 至 150 hPa 中间层均低于 150 hPa 以上层。低于 300 hPa 时早晨的 BIAS 低于黄昏，但上层的 BIAS 较高。此外，500 hPa~150 hPa中间层BIAS值均为正值，其他层层BIAS值均为负值。总体而言，AIRS反演温度较为可靠，可用于塔克拉玛干沙漠的进一步研究。
The Taklimakan Desert, the world's second largest desert, plays an important role in regional climate change. Previous studies on its spatial temperature features suffered from sparse conventional detection data, but the Atmospheric Infrared Sounder (AIRS) provides excellent temperature retrievals with high spatiotemporal resolution. Validation of AIRS temperature retrievals over desert regions with high land-surface emissivity, the key contributor to inversion error, is essential before using these data in regional weather/climate modeling. This paper examines the correlation coefficients, root mean square error (RMSE) and mean BIAS between AIRS-retrieved atmospheric temperature data and radiosonde observations (RAOBs) in the Taklimakan Desert hinterland and oases in the morning and at dusk. Firstly, the AIRS retrievals are consistent with RAOBs and are more consistent in the morning than at dusk. The consistency is better over a small-scale desert oasis than over a large-scale oasis in the morning and exhibits the opposite trend at dusk. The correlation coefficient over the hinterland is high in the morning but negative at dusk due to high desert-surface emissivity. Second, the RMSEs, which are all smaller than 3 K, are generally higher over desert sites than over oasis sites and slightly lower over a small-scale oasis than over a large-scale oasis in the morning. At dusk, the RMSEs are higher over desert sites than over oases and slightly higher over a small-scale oasis than over a large-scale oasis. Furthermore, the RMSEs are generally higher in the morning than at dusk over a large-scale oasis and lower in the morning than at dusk over a small-scale oasis. Third, the absolute mean BIAS values are mostly lower than 1 K. In the morning, relative to RAOB temperatures, the retrieval temperatures are higher over desert sites but lower over oasis sites. At dusk, the retrieval temperatures are lower than RAOB temperatures over both desert and oasis sites. The retrieval temperatures are higher than RAOB temperatures over desert sites in the morning but slightly lower at dusk. Most absolute mean BIAS values are higher in the morning than at dusk over both oasis and desert sites. Finally, the consistency between the AIRS and RAOB temperature data is high from 700 hPa to 100 hPa in the morning and from 700 hPa to 300 hPa at dusk. The difference between the AIRS and RAOB temperature data is generally higher in the morning than that at dusk. The RMSE differences between the AIRS and RAOB data are slightly lower in the morning than at dusk and are lower in the middle layers between 700 hPa and 150 hPa than in the layers above 150 hPa during both the morning and night. The BIAS is lower in the morning than at dusk below 300 hPa but higher in the upper layers. Moreover, the BIAS value is positive in the middle layers between 500 hPa and 150 hPa and negative at other levels at both times. Generally, the AIRS retrieval temperatures are reliable and can be used in further studies in the Taklimakan Desert.